In a known image forming apparatus such as a copier, a printer, and a facsimile machine using an electrophotographic system, toner is supplied to an electrostatic latent image formed on an image carrier (photosensitive drum) to develop the same, whereby a toner image is formed on the image carrier. When the toner image is transferred onto a sheet and subjected to a predetermined fixing process, an image is formed on the sheet.
In addition, in a known image forming apparatus, a cleaning blade contacts a photosensitive drum to clean up toner remaining on the photosensitive drum. Moreover, in a known technology, a photosensitive drum reciprocates in its axial direction in order to prevent foreign matter caught in the tip of a cleaning blade from scratching a surface of the photosensitive drum (streak uneven abrasion).
In the technology, the photosensitive drum reciprocates with a pair of cams arranged at one end in the axial direction of the photosensitive drum. Each of the pair of cams has two convex portions and two concave portions along its circumferential direction. When the convex portions of the cams sequentially contact each other and the concave portions of the cams sequentially contact each other, the photosensitive drum makes two round trips while rotating one revolution.